Former Florida governor Jeb Bush and other Republicans blame President Obama for the rise of the Islamic State terrorist group. (Alan Diaz/AP)

One by one, nearly a dozen GOP presidential hopefuls took the stage here last weekend for a Lincoln Dinner, each different in style and stature but all joining a rising Republican chorus that lays blame for the Islamic State terrorist group squarely at the feet of President Obama.

“If you fought in Iraq, it worked. It’s not your fault it’s going to hell. It’s Obama’s fault,” Sen. Lindsey O. Graham (S.C.) said to cheers.

Even the event’s timing — hours after U.S. Special Operations killed a key Islamic State leader — did little to alter the pitch. “It’s a great day, but it’s not a strategy,” said former Florida governor Jeb Bush.

After more than a decade bearing the political burden of Iraq, Republicans are making a dogged effort to shed it by arguing that the Islamic State’s gruesome ascent is a symptom of Obama’s foreign policy, rather than a byproduct of the 2003 invasion they once championed.

Chaos in the city of Ramadi, which this week fell under the control of Islamic State militants, has only intensified the Republican outcry.

Speaking at the Freedom Summit in South Carolina, Republican presidential candidate Marco Rubio quoted a line from the movie “Taken,” saying, ‘We will look for you. We will find you and we will kill you.’” (Reuters)

“This deterioration of our physical and ideological strength has led to a world far more dangerous than when President Obama entered office,” Sen. Marco Rubio (R-Fla.) said in a speech this month. “We’ve seen [the Islamic State] sweep across multiple states, commit brutal atrocities and attempt to establish a caliphate.”

The rapid move to shift responsibility is at the core of the GOP’s plan to define 2016 as a foreign-policy election. Anxious about demographic trends and the leftward drift of the electorate on social issues, many Republicans hope to seize on global unrest and offer voters a steady hand.

Reframing the way voters think about the Islamic State, which is also known as ISIS, has thus become a critical endeavor for the GOP field — especially as former secretary of state Hillary Rodham Clinton, who is linked closely to Obama’s Iraq policies, emerges as the likely Democratic nominee.

At the least, it is an attempt to have Iraq seen as a shared failure, begun by a Republican president and a Republican-controlled Congress but inherited and fumbled by Democrats.

“They’ve pushed the pendulum of blame in Obama’s direction,” said Ron Bonjean, a veteran GOP consultant. “The Republican candidates don’t have to do a whole lot because Americans are scratching their heads about what’s going on in Iraq, but by speaking together, they’ve raised the volume.”

The gambit has already been fraught with difficulties, however. In the past month, the most memorable part of the GOP race has been the contenders’ acknowledgment, at times made uneasily, that going into Iraq based on flawed intelligence reports was a mistake.

Speaker of the House John Boehner is demanding that President Obama develops a new strategy on dealing with Islamic State militants in the wake of the group’s occupation of the city Ramadi in Iraq. (Reuters)

Jeb Bush, in particular, has found himself tripping up as he recasts the cause and consequences of the Islamic State, asserting that Obama has shown weakness and destabilized the region by pulling U.S. troops out of Iraq, while dealing awkwardly with the lingering unpopularity of George W. Bush.

“Your brother created ISIS,” Ivy Ziedrich, a Nevada college student and Democrat, told Bush last week in a confrontational exchange that quickly went viral online and on television.

Bush contests that point of view. “ISIS didn’t exist when my brother was president,” he said Wednesday at a campaign stop in New Hampshire. “There were mistakes made in Iraq, for sure, but the surge created a fragile but stable Iraq that the president could have built on.

“He made the decision to get out. I don’t begrudge him that, but it was a decision made based on a campaign promise, based on conditions in Iraq at the time, and I think we’re now paying a price for it.”

Clinton, who was in Iowa this week for events, told reporters Tuesday that her vote in support of the Iraq invasion was a mistake, echoing an admission she made in her recent State Department memoir. She also expressed reluctance about reengaging militarily in the country.

Few, if any, of her potential primary rivals have made an issue of Iraq, but it is an area where Clinton allies privately acknowledge she could be vulnerable to attack.

“The United States is doing what it can, but ultimately this has to be a struggle that the Iraqi government and the Iraqi people are determined to win for themselves,” Clinton said. “We can provide support, but they’re going to have to do it.”

Most Republicans have pushed for a more muscular approach to Iraq, sensing that voters may look at the atrocities committed by the Islamic State and seek a strong rebuke by the United States. But they have leaned on fiery rhetoric over specific proposals.

“They want to bring back a 7th-century version of jihad. So here’s my suggestion: We load up our bombers, and we bomb them back to the 7th century,” former senator Rick Santorum of Pennsylvania said at the recent Iowa forum.

The political endgame for Republicans is a general election where Clinton can be portrayed as someone who initially backed the U.S. mission but did not see it through. In that sense, foisting blame on Obama is only the first step in the GOP’s aims.

“President Obama and Secretary Clinton hastily withdrew troops, threw away the gains of the surge, and embarked on a broader policy of pivoting away from the Middle East,” Wisconsin Gov. Scott Walker (R), a likely 2016 candidate, wrote on his Facebook page last week.

The turn is emblematic, too, of how the Republican Party is still grappling with the public’s disfavor of the Iraq war and their ties to it. Knowing their ownership of the invasion in the eyes of voters has not faded, they would like to distance themselves from the messy debate over weapons of mass destruction and make the Islamic State — how it rose and how to stop it — the central political battleground on foreign policy.

The emphasis is a departure from how Mitt Romney campaigned against Obama in 2012. While Romney questioned Obama’s handling of Iraq and his inclination against keeping a residual force there, the Islamic State had yet to emerge as the sprawling power it is today.

GOP strategist Steve Schmidt, who guided the 2008 presidential campaign of Sen. John McCain (R-Ariz.), said Republicans will soon need to offer concrete policy ideas.

“They’ve been caught so far in these traps of hypothetical questions about Iraq and have been critical of the president, but the real challenge will be in laying out a full and substantive case against the administration,” he said.

In Ramadi, the United States is helping the Iraqi military regroup after soldiers retreated from there last weekend.

Overall, it is estimated that the campaign against Islamic State extremists in Iraq will take three years or more. “This is a really formidable enemy,” a U.S. official said, calling the setbacks and surprises inevitable. “It’s going to be a very long, multiple-year campaign.” The official spoke on the condition of anonymity to discuss the fall of Ramadi more freely.

At the White House on Tuesday, press secretary Josh Earnest downplayed the ongoing clashes as indicative of a collapsing Iraq, as some Republicans have charged. Other periods have been “followed shortly by important progress,” he said. “The president is mindful that this is not a short-term proposition.”

For Republicans, questions remain about whether they can convince their rank-and-file members that they can offer a solution for a country that has haunted them.

Sen. Rand Paul (R-Ky.), a libertarian-leaning presidential candidate, wondered aloud last week whether the turmoil in Iraq is entirely an outgrowth of Obama’s stewardship and sounded less than enthusiastic about more U.S. intervention.

“We have to question: Is Iraq more stable or less stable since [former Iraqi leader Saddam] Hussein is gone? Is there more chaos or less chaos?” he asked at the GOP dinner here. “Is ISIS more of a threat now because of the instability?”

Ed O’Keefe in Portsmouth, N.H., and Carol Morello in Washington contributed to this report.